Arrangement for disintegrating slivers of bark in debarking machines of the so-called hollow-head type



1958 P. G. BRUNDELL ETAL 2,860,672

ARRANGEMENT FOR DISINTEGRATING SLIVERS OF BARK IN DEBARKING MACHINES OF THE SO-CALLED HOLLOW-HEAD TYPE 2 Sheets-Sheet 2 Filed NOV. 13, 1956 radial direction relative to the axis of the rotor.

ARRANGEMENT FOR DISINTEGRATIN G SLIVERS OF BARK IN DEBARKING MACHINES OF THE SO-CALLED HOLLOW-HEAD TYPE Per Gunnar Brundell and Karl Erik Arnold Jonsson, Gavle, Sweden, assignors to Soderhamns Verkstader Aktiebolag, Soderhamn, Sweden Application November 13, 1956, Serial No. 621,788 Claims priority, application Sweden December 6, 1955 10 Claims. (Cl. 144-208) The present invention refers to an arrangement in debarking machines of the so-called hollow-head type, in which successive logs are fed forward in a straight path and restrained against rotation while a plurality, of debarking tools carried by a rotating holder (rotor) surrounding the logs are resiliently actuated forward and against the logs. The tools are swingable about axes which are substantially parallel to the axis of rotation of the rotor and are actuated or biased towards a log to be debarked by a continuously acting elastic force, which when the debarking machine is running idle, keeps the tips of the tools adjacent to the axis of rotation of the rotor. When a log is fed into the machine and is pressed against the debarking tools these will withdraw from the axis of rotation of the rotor under the influence of the rotation of the rotor and their engagement with the end of the log until the tips of the tools come up onto the surface of the log and the debarking proper commences, during which the tips of the tools slide or ride upon the wood surface of the log and shear or scrape off the bark in a tangential direction.

In debarking machines of the type under consideration, the linear speed of the debarking tools over the surface of the wood is very high and particularly since the tools are continuously maintained in contact with the wood surface, most types of bark are immediately torn to small pieces and thrown into a bark-collecting space in the machine in a direction that is substantially tangential to the wood surface. The bark is then thrown out of this collecting space through a tangential outlet from this space. However, with some types of bark, the rotational speed is not high enough to prevent the formation of long silvers of bark. Some of these slivers become caught by the debarking tools and impair the action thereof by adding so much weight to the same, that the debarking pressure at the tips of the tools is radically decreased due to centrit'ugal forces exerted by the slivers of bark. To avoid difficulties of this character to a considerable degree, we have proposed in our copending application, Serial No. 517,832, now Patent No. 2,788,024, granted. April 9, 1957 to mount one or more knife or countersteel members of rectangular section to extend in an approximately The dimensions of these countersteels are such that a comparatively small clearance space will exist between them and a planar path of the revolving debarking tools, which path is perpendicular to the axis of the rotor and the front face of which is defined by a protruding sharp edge on each debarking tool. This clearance space should be less than /2" and preferably about /8". When the tools are working on a medium-sized log, a portion of the sharp edge of each tool will pass the countersteel. If there is a bark sliver on this portion of the edge it will be cut or torn off between the countersteel and the adjacent and relatively moving sharp edge of a tool.

However, when the tools are working continuously on wood of logs, the dimensions of which are small relative United States Patent to the maximum log for which the machine is intended,

,a considerable amount of slivers can accumulate around the edges of the tools without their coming within the sphere of operation of the fixed countersteel. We now have provided a movable countersteel or shearing mem- ,presses and the like. The invention is principally characterized by having each of the swingable debarking tools including a sharp edge directed toward an oncoming log and revolving in a planar path that extends transversely to the axis of rotation of the rotor, by having a countersteel mounted to be normally stationary relative to the revolving movement of the too-ls, but capable of swinging movement toward and away from the oncoming direction of the revolving tools and provided with a sharp edge close to said planar path and confronting the oncoming tools, and by having means for moving the countersteel toward the oncoming toolsin order to utilize the rotational movement of the rotor to cut 01f, saw oil or tear off the slivers of bark that may come between the edges of the oncoming tools and said sharp edge of the embodiments of the invention illustrated in the attached drawings, where Fig. l is a fragmentary end view of a debarking machine seen from the infeed side and provided with a device for disintegrating slivers of bark according. to the invention,

Fig. 2 is a cross-sectional view along line 2-2 in Fig. 1,

Fig. 3 illustrates perspectively the coupling of one of the feed rolls of the debarking machine with a countersteel according to the invention and shows a debarking tool cooperating with this countersteel,

Fig. 3A is a cross-sectional view of a component shown in Fig. 3,

Fig. 4 is a cross-sectional view along line 4-4 of Fig. 3 illustrating the shape of the countersteel. illustrated in that figure, i

Fig. 5 is a cross-sectional view along line 5-5 of Fig. 3 illustrating the sharp edge of the debarking tool illustrated in that figure,

Fig. 6 is a fragmentary end view of another embodiment of the disintegrating device according to the invention,

Fig. 7 illustrates on an enlarged scale a sectional view taken along line 77 of Fig. 6 and shows the spring arrangement co-operating with the countersteel shown in said Figure 6,

Fig. 8 is a fragmentary end view of a second modification of a countersteel mounted for co-operation with a debarking tool, the countersteel being manually operated,

Figs. 9 and 10 are fragmentary end views that illustrate two further embodiments of the disintegrating device according to the invention, and

Fig. 11 is a view partly in longitudinal section and partly in elevation illustrating on an enlarged scale a component shown in Fig. 10. I

In Fig. 1 the frame of a debarking machine of the hollow-head type is designated by 1, and 2, 3 and reference characters 4 denote rotatable feed rolls fixed to swingable arms 5, 6 and 7, which are coupled together by means of links 8, 9 and 10. In the frame is journaled a rotor 11, which carries swingably arranged debarking tools 12. To the feed-roll arm 7 is coupled a countersteel 13 swingably arranged to move in a path perpendicular to the feed direction and parallel to a path of revolution of the debarking tools. The countersteel or shearing member 13 is fixed to a shaft 14 which is journaled in a bearing 15 that is rigidly connected to a plate attached to the frame on the infeed side of the machine. To the opposite end of the shaft 14 is fixed one end of a'lever 16, the other end of whichfits over a pin 17 rigidly connected to a cylinder 18 housing a spring 48, and in which cylinder isv disposed a rod 19 fitted for axial movement relative to the cylinder 18. This rod 19 has its lower end bent and swingably connected with a bracket 7 on the feed-roll arm 7, see Figs. 3 and 3A. The debarking tool 12 is provided with a sharp edge 20 facing an oncoming log, said edge, as the tool revolves, defining a plane that is perpendicular to the axis of rotation of the rotor. In order to facilitate the cutting off, sawing off or tearing off of the slivers of bark the countersteel is provided with a sharp edge 21 which confronts the oncoming revolving tools 12 and is in the shape of a saw. Upon contact with a log being fed to the machine, the feed rolls 2, 3 and 4 will be moved outwardly from the center line of the machine and onto the periphery of the log, thus correspondingly swinging arms 5, 6 and 7, whereby the arm 7, by the link 19, the cylinder 18, the pivot pin 17, the lever 16 and the shaft 14, will also swing the countersteel 13 but in an opposite direction from said center line.

The cutting or sawing action aimed at is always effected on bark slivers that may come between the sawshaped edge 21 of the countersteel 13 and the edge 20 of the oncoming revolving tool 12. The cylinder 18 is so arranged that when the feed arm has closed itself after the passage of a log, the countersteel can bear against the surface of that log until that log also passes the countersteel, at which time this steel moves to its inner position. the debarking tool from slivers of bark along its whole length. In this embodiment the swingably arranged countersteel is automatically adjustable with respect to the turning position of the swingably arranged feed-roll arm 7 and alsothe tools 12.

Thus the countersteel will disengage In Figs. 6, 9 and'lO a feed-roll arm is designated by V 7 and a feed roll carried by said arm is designated by 4, the countersteel being designated by 13. Said countersteel is swingably mounted on a turnable shaft 22 to which is fixed a lever 23 which is held in contact with a 'cam 24 fixed to a hub 25 on the feed roll arm 7. The frame of the debarking machine of the hollow-head type is designated by 1.

In the embodiment illustrated in Figs. 6 and 7 the shaft 22 is journaled in a box 26 mounted on the frame 1. As described later on, the shaft 22 is actuated by one end of a spiral-shaped spring 37, the other end being fixed to the box 26. I

In each of the embodiments illustrated in Figs. 9 and 10 the lever 23 on the shaft 22 of the countersteel 13 is held in contact with the cam 24 on the hub 25 of the feed-roll arm 7 by means of either a tension rubber spring 27 (Fig. 9) or 27' (Fig. 10) fixed to the frame 1. In these two embodiments the shaft 22 of the countersteel 13 is journaled in a bearing 28 fixed to the frame 1.

In the embodiments illustrated in Figs. 6, 9 and 10 thecountersteel and the feed roll are shown in two ditferent positions in relation to logs of different diameters.

In the device illustrated in Fig. 7 the countersteel 13 is fixed to the shaft 22, which is journalled by means of two ball bearings 34 in the box 26. This box is surrounded by a hood 35 fixed to the shaft by means of splines 36. On this hood is clamped a lip-carrying band, the lip constituting the lever 23. This lip is held in contact with the cam 24 by means of the spiral-shaped spring 37 fixed at one of its ends to the box 26 and at its other end to the turnable hood 35.

Outward movement of the feeding device, i. e. when the feed rolls climb to the end of an oncoming log, always produces an equal or somewhat larger swing of the steel 13 from its innermost position, because of the aforesaid camming action between the lever 23 on the countersteel shaft 22 and the cam 24 mounted on the hub 25 of one of the interlinked feed-roll arms 7.

Inward movement of the feed-roll arm 7, however, does not necessarily produce a similar movement of the countersteel 13. The lever 23 remains in contact with the cam 24 when the force of the spring 37 is not overruled by forces acting on the working part of the countersteel.

For example, in the often encountered case when the feed rolls snap together after passing off a big log, the countersteel, for the short moment it takes the log to travel from the back end of the feed rolls to the debarking tools moves into contact with the surface of the log and is held against said surface only by the force generated by the spring. The contact between the lever and the cam is then broken until the spring pulls the countersteel toward the roller 4 after passage of the end of the log. By incorporating a retarding or timing device in the spring this swinging movement of the countersteel toward said roller 4 can be decreased or completely avoided. Accordingly, the retarding device is as shown in Fig. 11. The countersteel 13 is linked to a plunger 34 movable within a cylinder 35' surrounded by a rubber sleeve 36 mounted to provide an annular space 37 between the interior of sleeve 36' and the exterior of cylinder 35. The cylinder 35 is provided with three axially spaced ports 33 to provide for flow of oil between the cylinder 35 and the annular space 37 and vice versa. By pulling out the plunger 34' to the dotted-line position 39, the cylinder 35' can be supplied with oil by screwing out a screw plug 46) after removing an end closure plug 41. By a proper selection of the viscosity of the oil put into cylinder 35 and the size of the ports 38, it is possible to vary within liberal limits the speed with which the countersteel moves toward the axis of rotation of the machine. Thus, during operation, when the arm 7 swings outwards, the cam 24 earns the countersteel 13 outwards but in an opposite direction. When the arm 7 swings in toward the axis of the rotor after a log has passed off the feed rolls, the inward movement of the plunger 34' is retarded by the oil which has to be forced out of the ports 38 into the annular space 37. This, accordingly, retards the movement of the countersteel 13 back toward the axis of the rotor. Other cases when the contact between the cam and the lever is broken is when the countersteel is swung out by forces produced by counterdescribed embodiments, but can be varied in a number of different ways within the scope of the invention.

What we claim is:

1. In a debarking machine of the so-called hollowhead type having a tool-carrying rotor, an arrangement for disintegrating bark in the shape of long slivers and for removing from the debarking tools such bark that tends to adhere to the tools and prevent their operation, each of these debarking tools being providedwith an edge directed toward an oncoming log and revolving in a planar path transverse to the axis of rotation of the rotor, said arrangement comprising a countersteel normally stationary relative to the tools revolving with said rotor, said steel being mounted for swinging movement toward and away from the oncoming revolving tools and provided with a sharp edge situated close to said planar path and in confronting relation to the oncoming tools as they revolve past said steel, and means for swinging the countersteel toward said oncoming tools in order to utilize the rotational movement of the rotor to cut off, saw off or tear off those slivers of bark that come between the log-directed edges of the oncoming tools and said sharp edge of the countersteel.

2. In a debarking machine as claimed in claim 1, in which said sharp edge on the countersteel is shaped as a saw in order to facilitate the cutting off, sawing off and tearing off respectively of such slivers of bark.

3. In a debarking machine as claimed in claim 1, and means to swing the countersteel away from the oncoming revolving tools in order to position the steel beyond the periphery of the path of an oncoming log, such position being automatically adjustable in relation to the diameter of such oncoming log.

4. In a debarking machine as claimed in claim 3, in which said means to swing the countersteel away from the oncoming tools includes an elastic coupling between the countersteel and a feed and/or guiding device located adjacent the infeed side of the debarking machine.

5. In an arrangement as claimed in claim 4, in which the elastic coupling includes a motion retarding mechanism slowing down the swinging movement of the countersteel in the direction toward the oncoming revolving tools.

6. In a debarking machine of the type including an annular rotor, debarking tools carried by the rotor and swingably mounted about fixed axes angularly spaced about the rotor for movement toward and away from the axis of the rotor, and in which each tool includes a sharp edge directed toward an oncoming log and moving with the rotor in a path transverse to the axis of rotation of the rotor, a combined log-feeding and bark-disintegrating mechanism for disintegrating and removing slivers of bark that might adhere to the tools comprising the combination of a plurality of feeding rolls, each mounted for rotation about an axis transverse to the axis of the rotor, arm means including an arm and mounting each roll and stationary pivot means for each arm means extending parallel to the rotor axis, but arranged radially outwards of the rotor and in mutually angularly spaced relation, link means interconnecting the respecting arm means for simultaneous movement, whereby an oncoming log in engaging the periphery of the speed rolls forces the same outwards to accommodate the circumference of varying size logs that are capable of passing through the rotor, the edge of the tool effecting in cooperation with the butt end of an oncoming log outward movement of the tools to a debarking position, a movable shear blade, means mounting said blade for turning movement about an axis parallel to the rotor axis, said blade being disposed to swing toward and away from the tools revolving with the rotor, but immediately adjacent the path of rotation of the sharp edge on each tool, so that any slivers of bark wrapped around or adhered to the tool can be sheared by the co-operation between the said sharp edges of the tool and the shear blade, and means interconnecting the shear blade with one of said arms that carries a feed roll for imparting movement to said shear blade in a direction opposite to the outward swinging movement of said arm.

7. In a debarking machine as claimed in claim 6 and which said last-mentioned means comprises a link mechanism pivotally connected at one end to one of said arms and a lever means connected at one end to said shear blade and at the other end to said link mechanism.

8. In a debarking machine as claimed in claim 6 and a cam follower means connected to said shear blade, said one of said arms having a cam thereon adapted to engage said cam follower means so that when said one arm swings outwards relative to the axis of the rotor in response to being engaged by an oncoming log, the cooperation between said cam and cam follower means swings said shear blade outwards in the opposite direction.

9. In a debarking machine as claimed in claim 8 and further including a spring connection between said cam follower means and said shear blade.

10. In a debarking machine of the type which includes a stator, a rotor journaled within the stator and carrying bark-removing tools, each said tool having a sharp edge facing an oncoming log and said tools being mounted for movement toward and away from the axis of such log, whereby the cooperative engagement between the butt end of an oncoming log effects outward movement of the tools to debarking position on the surface of such log; means for removing and/or disintegrating slivers of bark that might adhere to the tools comprising a shear blade, pivot means for the blade extending parallel to the axis of the rotor and carried by the stator, said shear blade being mounted for swinging movement in a path close to the path of movement of the sharp edges on said tools but immediately adja cent thereto and on the side of said edges directed toward an oncoming log; further pivot means being carried by the stator and extending parallel to the rotor axis and being mounted outwards of the pivot means for said shear blade, means carried by said last-mentioned pivot means and movable outwards of the axis of the rotor in response to being engaged by an oncoming log, and means connecting said last-mentioned means with the shear blade for imparting opposite swinging movement to the shear blade prior to an oncoming log engaging the edges of said tool means.

No references cited. 

